Finding sugar that's already been dyed black can be challenging, so you may end up having to make it yourself. The ingredients for homemade black sugar can be found in craft stores or online. You can use black sugar to decorate spooky Halloween baked goods or add flair to an "Over the Hill" cake. This method can also be used to dye flaked coconut.
Fill the sandwich baggie with 1/2 cup of sanding sugar. Sanding sugar is a large-grain sugar that sparkles like crystal, holds color well, and won't melt in hot conditions. You can find sanding sugar in the baking section of craft stores.
Add a pinch of black powdered food color. Powdered food coloring works best for coloring sugar because it spreads evenly and is ready to use right away. You can find powdered food coloring in the baking section of craft stores.
Shake the bag until the color is evenly distributed. You can use the sugar right away because powdered food coloring doesn't require any time to dry or set. Add more color if you want a deeper black.
Trying to mix powdered food colors to make black will often produce a dark gray color. Premade black food coloring is the best choice for this.